Fastmail vs kasserver.com

Fastmail is used by more websites in our catalog: 1,580 use Fastmail and 736 use kasserver.com.

Fastmail sites have the higher median Ahrefs Domain Rating (Fastmail: 38, kasserver.com: 29).

Between 2026-06 and 2026-07, Fastmail went from 0.22% to 0.18% of all tracked sites, while kasserver.com went from 0.10% to 0.08%. kasserver.com is gaining ground faster in our index.

No. A site runs a single email host, so Fastmail and kasserver.com are mutually exclusive.

Adoption is counted from Site Stats Database's own crawl; Domain Rating comes from Ahrefs and traffic from DataForSEO. Figures reflect the sites we track and refresh at least monthly.